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Tao Bao7197ee02015-12-05 21:21:27 -08001/*
2 * Copyright (C) 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17/*
18 * This program verifies the integrity of the partitions after an A/B OTA
19 * update. It gets invoked by init, and will only perform the verification if
20 * it's the first boot post an A/B OTA update.
21 *
Tianjie Xu3958a952017-03-01 15:31:25 -080022 * Update_verifier relies on dm-verity to capture any corruption on the partitions
23 * being verified. And its behavior varies depending on the dm-verity mode.
24 * Upon detection of failures:
25 * enforcing mode: dm-verity reboots the device
26 * eio mode: dm-verity fails the read and update_verifier reboots the device
27 * other mode: not supported and update_verifier reboots the device
28 *
29 * After a predefined number of failing boot attempts, the bootloader should
Tianjie Xud007cf22016-02-29 16:08:06 -080030 * mark the slot as unbootable and stops trying. Other dm-verity modes (
31 * for example, veritymode=EIO) are not accepted and simply lead to a
32 * verification failure.
Tao Bao7197ee02015-12-05 21:21:27 -080033 *
34 * The current slot will be marked as having booted successfully if the
35 * verifier reaches the end after the verification.
Tao Bao7197ee02015-12-05 21:21:27 -080036 */
37
Tao Bao83b07802017-04-26 14:30:56 -070038#include "update_verifier/update_verifier.h"
39
Tianjie Xub0ac8722017-01-18 18:41:53 -080040#include <dirent.h>
Tianjie Xud007cf22016-02-29 16:08:06 -080041#include <errno.h>
42#include <fcntl.h>
43#include <stdio.h>
Tao Bao7197ee02015-12-05 21:21:27 -080044#include <string.h>
Tianjie Xu3958a952017-03-01 15:31:25 -080045#include <unistd.h>
Tao Bao7197ee02015-12-05 21:21:27 -080046
Tianjie Xu8fa8f0b2017-04-27 11:47:35 -070047#include <algorithm>
Wei Wang5226f472017-08-02 10:27:31 -070048#include <future>
Tianjie Xud007cf22016-02-29 16:08:06 -080049#include <string>
50#include <vector>
51
52#include <android-base/file.h>
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -070053#include <android-base/logging.h>
Tianjie Xud007cf22016-02-29 16:08:06 -080054#include <android-base/parseint.h>
Tao Bao4f8d2172017-01-13 15:36:32 -080055#include <android-base/properties.h>
Tianjie Xud007cf22016-02-29 16:08:06 -080056#include <android-base/strings.h>
57#include <android-base/unique_fd.h>
Connor O'Brienad43d2d2016-11-21 12:47:33 -080058#include <android/hardware/boot/1.0/IBootControl.h>
Tianjie Xu3958a952017-03-01 15:31:25 -080059#include <cutils/android_reboot.h>
Connor O'Brienad43d2d2016-11-21 12:47:33 -080060
Tao Bao160514b2017-11-04 00:08:08 -070061#include "otautil/rangeset.h"
62
Connor O'Brienad43d2d2016-11-21 12:47:33 -080063using android::sp;
64using android::hardware::boot::V1_0::IBootControl;
65using android::hardware::boot::V1_0::BoolResult;
66using android::hardware::boot::V1_0::CommandResult;
Tao Bao7197ee02015-12-05 21:21:27 -080067
Tianjie Xub0ac8722017-01-18 18:41:53 -080068// Find directories in format of "/sys/block/dm-X".
69static int dm_name_filter(const dirent* de) {
70 if (android::base::StartsWith(de->d_name, "dm-")) {
71 return 1;
72 }
73 return 0;
74}
75
Tianjie Xu3958a952017-03-01 15:31:25 -080076static bool read_blocks(const std::string& partition, const std::string& range_str) {
Tianjie Xu5a176c02017-03-31 16:36:12 -070077 if (partition != "system" && partition != "vendor") {
78 LOG(ERROR) << "partition name must be system or vendor: " << partition;
79 return false;
80 }
Tianjie Xub0ac8722017-01-18 18:41:53 -080081 // Iterate the content of "/sys/block/dm-X/dm/name". If it matches "system"
82 // (or "vendor"), then dm-X is a dm-wrapped system/vendor partition.
83 // Afterwards, update_verifier will read every block on the care_map_file of
84 // "/dev/block/dm-X" to ensure the partition's integrity.
Tao Bao83b07802017-04-26 14:30:56 -070085 static constexpr auto DM_PATH_PREFIX = "/sys/block/";
Tianjie Xub0ac8722017-01-18 18:41:53 -080086 dirent** namelist;
87 int n = scandir(DM_PATH_PREFIX, &namelist, dm_name_filter, alphasort);
88 if (n == -1) {
89 PLOG(ERROR) << "Failed to scan dir " << DM_PATH_PREFIX;
90 return false;
91 }
92 if (n == 0) {
93 LOG(ERROR) << "dm block device not found for " << partition;
94 return false;
95 }
96
Tao Bao83b07802017-04-26 14:30:56 -070097 static constexpr auto DM_PATH_SUFFIX = "/dm/name";
98 static constexpr auto DEV_PATH = "/dev/block/";
Tianjie Xub0ac8722017-01-18 18:41:53 -080099 std::string dm_block_device;
100 while (n--) {
101 std::string path = DM_PATH_PREFIX + std::string(namelist[n]->d_name) + DM_PATH_SUFFIX;
102 std::string content;
103 if (!android::base::ReadFileToString(path, &content)) {
104 PLOG(WARNING) << "Failed to read " << path;
David Zeuthen8ed97382017-05-08 13:41:28 -0400105 } else {
106 std::string dm_block_name = android::base::Trim(content);
107#ifdef BOARD_AVB_ENABLE
108 // AVB is using 'vroot' for the root block device but we're expecting 'system'.
109 if (dm_block_name == "vroot") {
110 dm_block_name = "system";
Tianjie Xub0ac8722017-01-18 18:41:53 -0800111 }
David Zeuthen8ed97382017-05-08 13:41:28 -0400112#endif
113 if (dm_block_name == partition) {
114 dm_block_device = DEV_PATH + std::string(namelist[n]->d_name);
115 while (n--) {
116 free(namelist[n]);
117 }
118 break;
119 }
Tianjie Xub0ac8722017-01-18 18:41:53 -0800120 }
121 free(namelist[n]);
122 }
123 free(namelist);
124
125 if (dm_block_device.empty()) {
126 LOG(ERROR) << "Failed to find dm block device for " << partition;
127 return false;
128 }
Tao Bao4f8d2172017-01-13 15:36:32 -0800129
130 // For block range string, first integer 'count' equals 2 * total number of valid ranges,
131 // followed by 'count' number comma separated integers. Every two integers reprensent a
132 // block range with the first number included in range but second number not included.
133 // For example '4,64536,65343,74149,74150' represents: [64536,65343) and [74149,74150).
Tao Bao160514b2017-11-04 00:08:08 -0700134 RangeSet ranges = RangeSet::Parse(range_str);
135 if (!ranges) {
136 LOG(ERROR) << "Error parsing RangeSet string " << range_str;
Tao Bao4f8d2172017-01-13 15:36:32 -0800137 return false;
138 }
Tao Bao160514b2017-11-04 00:08:08 -0700139
140 // RangeSet::Split() splits the ranges into multiple groups with same number of blocks (except for
141 // the last group).
142 size_t thread_num = std::thread::hardware_concurrency() ?: 4;
143 std::vector<RangeSet> groups = ranges.Split(thread_num);
Tao Bao4f8d2172017-01-13 15:36:32 -0800144
Wei Wang5226f472017-08-02 10:27:31 -0700145 std::vector<std::future<bool>> threads;
Tao Bao160514b2017-11-04 00:08:08 -0700146 for (const auto& group : groups) {
147 auto thread_func = [&group, &dm_block_device, &partition]() {
Wei Wang5226f472017-08-02 10:27:31 -0700148 android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(dm_block_device.c_str(), O_RDONLY)));
149 if (fd.get() == -1) {
150 PLOG(ERROR) << "Error reading " << dm_block_device << " for partition " << partition;
Tianjie Xu8fa8f0b2017-04-27 11:47:35 -0700151 return false;
152 }
Wei Wang5226f472017-08-02 10:27:31 -0700153
Tao Bao160514b2017-11-04 00:08:08 -0700154 static constexpr size_t kBlockSize = 4096;
155 std::vector<uint8_t> buf(1024 * kBlockSize);
Wei Wang5226f472017-08-02 10:27:31 -0700156
Tao Bao160514b2017-11-04 00:08:08 -0700157 size_t block_count = 0;
158 for (const auto& range : group) {
159 size_t range_start = range.first;
160 size_t range_end = range.second;
Wei Wang5226f472017-08-02 10:27:31 -0700161 if (lseek64(fd.get(), static_cast<off64_t>(range_start) * kBlockSize, SEEK_SET) == -1) {
162 PLOG(ERROR) << "lseek to " << range_start << " failed";
163 return false;
164 }
165
166 size_t remain = (range_end - range_start) * kBlockSize;
167 while (remain > 0) {
168 size_t to_read = std::min(remain, 1024 * kBlockSize);
169 if (!android::base::ReadFully(fd.get(), buf.data(), to_read)) {
170 PLOG(ERROR) << "Failed to read blocks " << range_start << " to " << range_end;
171 return false;
172 }
173 remain -= to_read;
174 }
Tao Bao160514b2017-11-04 00:08:08 -0700175 block_count += (range_end - range_start);
Wei Wang5226f472017-08-02 10:27:31 -0700176 }
Tao Bao160514b2017-11-04 00:08:08 -0700177 LOG(INFO) << "Finished reading " << block_count << " blocks on " << dm_block_device;
Wei Wang5226f472017-08-02 10:27:31 -0700178 return true;
179 };
180
181 threads.emplace_back(std::async(std::launch::async, thread_func));
Tao Bao4f8d2172017-01-13 15:36:32 -0800182 }
Tianjie Xud007cf22016-02-29 16:08:06 -0800183
Wei Wang5226f472017-08-02 10:27:31 -0700184 bool ret = true;
185 for (auto& t : threads) {
186 ret = t.get() && ret;
187 }
188 LOG(INFO) << "Finished reading blocks on " << dm_block_device << " with " << thread_num
189 << " threads.";
190 return ret;
Tianjie Xud007cf22016-02-29 16:08:06 -0800191}
192
Tao Bao5a1dee02017-07-21 15:15:31 -0700193// Returns true to indicate a passing verification (or the error should be ignored); Otherwise
194// returns false on fatal errors, where we should reject the current boot and trigger a fallback.
195// Note that update_verifier should be backward compatible to not reject care_map.txt from old
196// releases, which could otherwise fail to boot into the new release. For example, we've changed
197// the care_map format between N and O. An O update_verifier would fail to work with N
198// care_map.txt. This could be a result of sideloading an O OTA while the device having a pending N
199// update.
Tao Bao83b07802017-04-26 14:30:56 -0700200bool verify_image(const std::string& care_map_name) {
Tao Bao5a1dee02017-07-21 15:15:31 -0700201 android::base::unique_fd care_map_fd(TEMP_FAILURE_RETRY(open(care_map_name.c_str(), O_RDONLY)));
202 // If the device is flashed before the current boot, it may not have care_map.txt
203 // in /data/ota_package. To allow the device to continue booting in this situation,
204 // we should print a warning and skip the block verification.
205 if (care_map_fd.get() == -1) {
206 PLOG(WARNING) << "Failed to open " << care_map_name;
Tianjie Xud007cf22016-02-29 16:08:06 -0800207 return true;
Tao Bao5a1dee02017-07-21 15:15:31 -0700208 }
209 // Care map file has four lines (two lines if vendor partition is not present):
210 // First line has the block partition name (system/vendor).
211 // Second line holds all ranges of blocks to verify.
212 // The next two lines have the same format but for vendor partition.
213 std::string file_content;
214 if (!android::base::ReadFdToString(care_map_fd.get(), &file_content)) {
215 LOG(ERROR) << "Error reading care map contents to string.";
216 return false;
217 }
218
219 std::vector<std::string> lines;
220 lines = android::base::Split(android::base::Trim(file_content), "\n");
221 if (lines.size() != 2 && lines.size() != 4) {
222 LOG(ERROR) << "Invalid lines in care_map: found " << lines.size()
223 << " lines, expecting 2 or 4 lines.";
224 return false;
225 }
226
227 for (size_t i = 0; i < lines.size(); i += 2) {
228 // We're seeing an N care_map.txt. Skip the verification since it's not compatible with O
229 // update_verifier (the last few metadata blocks can't be read via device mapper).
230 if (android::base::StartsWith(lines[i], "/dev/block/")) {
231 LOG(WARNING) << "Found legacy care_map.txt; skipped.";
232 return true;
233 }
234 if (!read_blocks(lines[i], lines[i+1])) {
235 return false;
236 }
237 }
238
239 return true;
Tianjie Xud007cf22016-02-29 16:08:06 -0800240}
241
Tianjie Xu3958a952017-03-01 15:31:25 -0800242static int reboot_device() {
243 if (android_reboot(ANDROID_RB_RESTART2, 0, nullptr) == -1) {
244 LOG(ERROR) << "Failed to reboot.";
245 return -1;
246 }
247 while (true) pause();
248}
249
Tao Bao83b07802017-04-26 14:30:56 -0700250int update_verifier(int argc, char** argv) {
Tao Bao7197ee02015-12-05 21:21:27 -0800251 for (int i = 1; i < argc; i++) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700252 LOG(INFO) << "Started with arg " << i << ": " << argv[i];
Tao Bao7197ee02015-12-05 21:21:27 -0800253 }
254
Chris Phoenix0157c782017-01-20 11:34:00 -0800255 sp<IBootControl> module = IBootControl::getService();
Connor O'Brienad43d2d2016-11-21 12:47:33 -0800256 if (module == nullptr) {
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700257 LOG(ERROR) << "Error getting bootctrl module.";
Tianjie Xu3958a952017-03-01 15:31:25 -0800258 return reboot_device();
Tao Bao7197ee02015-12-05 21:21:27 -0800259 }
260
Connor O'Brienad43d2d2016-11-21 12:47:33 -0800261 uint32_t current_slot = module->getCurrentSlot();
262 BoolResult is_successful = module->isSlotMarkedSuccessful(current_slot);
263 LOG(INFO) << "Booting slot " << current_slot << ": isSlotMarkedSuccessful="
264 << static_cast<int32_t>(is_successful);
Tao Bao7197ee02015-12-05 21:21:27 -0800265
Connor O'Brienad43d2d2016-11-21 12:47:33 -0800266 if (is_successful == BoolResult::FALSE) {
Tao Bao7197ee02015-12-05 21:21:27 -0800267 // The current slot has not booted successfully.
Tao Baodb57f0d2017-03-10 14:21:25 -0800268
David Zeuthen8ed97382017-05-08 13:41:28 -0400269#if defined(PRODUCT_SUPPORTS_VERITY) || defined(BOARD_AVB_ENABLE)
David Zeuthen1a0929c2017-08-07 18:47:27 -0400270 bool skip_verification = false;
Tao Bao4f8d2172017-01-13 15:36:32 -0800271 std::string verity_mode = android::base::GetProperty("ro.boot.veritymode", "");
272 if (verity_mode.empty()) {
David Zeuthen1a0929c2017-08-07 18:47:27 -0400273 // With AVB it's possible to disable verification entirely and
274 // in this case ro.boot.veritymode is empty.
275#if defined(BOARD_AVB_ENABLE)
276 LOG(WARNING) << "verification has been disabled; marking without verification.";
277 skip_verification = true;
278#else
Tianjie Xud007cf22016-02-29 16:08:06 -0800279 LOG(ERROR) << "Failed to get dm-verity mode.";
Tianjie Xu3958a952017-03-01 15:31:25 -0800280 return reboot_device();
David Zeuthen1a0929c2017-08-07 18:47:27 -0400281#endif
Tao Bao4f8d2172017-01-13 15:36:32 -0800282 } else if (android::base::EqualsIgnoreCase(verity_mode, "eio")) {
Tianjie Xu3958a952017-03-01 15:31:25 -0800283 // We shouldn't see verity in EIO mode if the current slot hasn't booted successfully before.
284 // Continue the verification until we fail to read some blocks.
285 LOG(WARNING) << "Found dm-verity in EIO mode.";
David Zeuthen1a0929c2017-08-07 18:47:27 -0400286 } else if (android::base::EqualsIgnoreCase(verity_mode, "disabled")) {
287 LOG(WARNING) << "dm-verity in disabled mode; marking without verification.";
288 skip_verification = true;
Tao Bao4f8d2172017-01-13 15:36:32 -0800289 } else if (verity_mode != "enforcing") {
Tianjie Xud007cf22016-02-29 16:08:06 -0800290 LOG(ERROR) << "Unexpected dm-verity mode : " << verity_mode << ", expecting enforcing.";
Tianjie Xu3958a952017-03-01 15:31:25 -0800291 return reboot_device();
292 }
293
David Zeuthen1a0929c2017-08-07 18:47:27 -0400294 if (!skip_verification) {
295 static constexpr auto CARE_MAP_FILE = "/data/ota_package/care_map.txt";
296 if (!verify_image(CARE_MAP_FILE)) {
297 LOG(ERROR) << "Failed to verify all blocks in care map file.";
298 return reboot_device();
299 }
Tianjie Xud007cf22016-02-29 16:08:06 -0800300 }
Tao Baodb57f0d2017-03-10 14:21:25 -0800301#else
302 LOG(WARNING) << "dm-verity not enabled; marking without verification.";
303#endif
Tao Bao7197ee02015-12-05 21:21:27 -0800304
Connor O'Brienad43d2d2016-11-21 12:47:33 -0800305 CommandResult cr;
306 module->markBootSuccessful([&cr](CommandResult result) { cr = result; });
307 if (!cr.success) {
308 LOG(ERROR) << "Error marking booted successfully: " << cr.errMsg;
Tianjie Xu3958a952017-03-01 15:31:25 -0800309 return reboot_device();
Tao Bao7197ee02015-12-05 21:21:27 -0800310 }
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700311 LOG(INFO) << "Marked slot " << current_slot << " as booted successfully.";
Tao Bao7197ee02015-12-05 21:21:27 -0800312 }
313
Tianjie Xu7b0ad9c2016-08-05 18:00:04 -0700314 LOG(INFO) << "Leaving update_verifier.";
Tao Bao7197ee02015-12-05 21:21:27 -0800315 return 0;
316}